1
|
Hampton D, Kedia S, Marder E. Alterations in network robustness upon simultaneous temperature and pH perturbations. J Neurophysiol 2024; 131:509-515. [PMID: 38264774 PMCID: PMC11305631 DOI: 10.1152/jn.00483.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 01/23/2024] [Accepted: 01/23/2024] [Indexed: 01/25/2024] Open
Abstract
Nervous systems have evolved to function consistently in the face of the normal environmental fluctuations experienced by animals. The stomatogastric nervous system (STNS) of the crab, Cancer borealis, produces a motor output that has been studied for its remarkable robustness in response to single global perturbations. Changes in environments, however, are often complex and multifactorial. Therefore, we studied the robustness of the pyloric network in the stomatogastric ganglion (STG) in response to simultaneous perturbations of temperature and pH. We compared the effects of elevated temperatures on the pyloric rhythm at control, acid, or base pHs. In each pH recordings were made at 11°C, and then the temperature was increased until the rhythms became disorganized ("crashed"). Pyloric burst frequencies and phase relationships showed minor differences between pH groups until reaching close to the crash temperatures. However, the temperatures at which the rhythms were disrupted were lower in the two extreme pH conditions. This indicates that one environmental stress can make an animal less resilient to a second stressor.NEW & NOTEWORTHY Resilience to environmental fluctuations is important for all animals. It is common that animals encounter multiple stressful events at the same time, the cumulative impacts of which are largely unknown. This study examines the effects of temperature and pH on the nervous system of crabs that live in the fluctuating environments of the Northern Atlantic Ocean. The ranges of tolerance to one perturbation, temperature, are reduced under the influence of a second, pH.
Collapse
Affiliation(s)
- David Hampton
- Biology Department and Volen Center, Brandeis University, Waltham, Massachusetts, United States
| | - Sonal Kedia
- Biology Department and Volen Center, Brandeis University, Waltham, Massachusetts, United States
| | - Eve Marder
- Biology Department and Volen Center, Brandeis University, Waltham, Massachusetts, United States
| |
Collapse
|
2
|
Durant A, Khodikian E, Porteus CS. Ocean acidification alters foraging behaviour in Dungeness crab through impairment of the olfactory pathway. GLOBAL CHANGE BIOLOGY 2023; 29:4126-4139. [PMID: 37158617 DOI: 10.1111/gcb.16738] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 03/26/2023] [Accepted: 03/29/2023] [Indexed: 05/10/2023]
Abstract
Crustacean olfaction is fundamental to most aspects of living and communicating in aquatic environments and more broadly, for individual- and population-level success. Accelerated ocean acidification from elevated CO2 threatens the ability of crabs to detect and respond to important olfactory-related cues. Here, we demonstrate that the ecologically and economically important Dungeness crab (Metacarcinus magister) exhibits reduced olfactory-related antennular flicking responses to a food cue when exposed to near-future CO2 levels, adding to the growing body of evidence of impaired crab behaviour. Underlying this altered behaviour, we find that crabs have lower olfactory nerve sensitivities (twofold reduction in antennular nerve activity) in response to a food cue when exposed to elevated CO2 . This suggests that near-future CO2 levels will impact the threshold of detection of food by crabs. We also show that lower olfactory nerve sensitivity in elevated CO2 is accompanied by a decrease in the olfactory sensory neuron (OSN) expression of a principal chemosensory receptor protein, ionotropic receptor 25a (IR25a) which is fundamental for odorant coding and olfactory signalling cascades. The OSNs also exhibit morphological changes in the form of decreased surface areas of their somata. This study provides the first evidence of the effects of high CO2 levels at multiple levels of biological organization in marine crabs, linking physiological and cellular changes with whole animal behavioural responses.
Collapse
Affiliation(s)
- Andrea Durant
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Canada
| | - Elissa Khodikian
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Canada
| | - Cosima S Porteus
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Canada
| |
Collapse
|
3
|
Energy-efficient network activity from disparate circuit parameters. Proc Natl Acad Sci U S A 2022; 119:e2207632119. [PMID: 36279461 PMCID: PMC9636970 DOI: 10.1073/pnas.2207632119] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Neural circuits can produce similar activity patterns from vastly different combinations of channel and synaptic conductances. These conductances are tuned for specific activity patterns but might also reflect additional constraints, such as metabolic cost or robustness to perturbations. How do such constraints influence the range of permissible conductances? Here we investigate how metabolic cost affects the parameters of neural circuits with similar activity in a model of the pyloric network of the crab
Cancer borealis
. We present a machine learning method that can identify a range of network models that generate activity patterns matching experimental data and find that neural circuits can consume largely different amounts of energy despite similar circuit activity. Furthermore, a reduced but still significant range of circuit parameters gives rise to energy-efficient circuits. We then examine the space of parameters of energy-efficient circuits and identify potential tuning strategies for low metabolic cost. Finally, we investigate the interaction between metabolic cost and temperature robustness. We show that metabolic cost can vary across temperatures but that robustness to temperature changes does not necessarily incur an increased metabolic cost. Our analyses show that despite metabolic efficiency and temperature robustness constraining circuit parameters, neural systems can generate functional, efficient, and robust network activity with widely disparate sets of conductances.
Collapse
|
4
|
The Effect of Doxapram on Proprioceptive Neurons: Invertebrate Model. NEUROSCI 2022. [DOI: 10.3390/neurosci3040041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The resting membrane potential enables neurons to rapidly initiate and conduct electrical signals. K2p channels are key in maintaining this membrane potential and electrical excitability. They direct the resting membrane potential toward the K+ equilibrium potential. Doxapram is a known blocker for a subset of K2p channels that are pH sensitive. We assessed the effects of 0.1 and 5 mM doxapram on the neural activity within the propodite-dactylopodite (PD) proprioceptive sensory organ in the walking legs of blue crabs (Callinectes sapidus). Results indicate that 0.1 mM doxapram enhances excitation, while the higher concentration 5 mM may over-excite the neurons and promote a sustained absolute refractory period until the compound is removed. The effect of 5 mM doxapram mimics the effect of 40 mM K+ exposure. Verapamil, another known K2p channel blocker as well as an L-type Ca2+ channel blocker, reduces neural activity at both 0.1 and 5 mM. Verapamil may block stretch activated channels in sensory endings, in addition to reducing the amplitude of the compound action potential with whole nerve preparations. These findings are notable as they demonstrate that doxapram has acute effects on neurons of crustaceans, suggesting a targeted K2p channel. The actions of verapamil are complex due to the potential of affecting multiple ion channels in this preparation. Crustacean neurons can aid in understanding the mechanisms of action of various pharmacological agents as more information is gained.
Collapse
|
5
|
Marder E, Kedia S, Morozova EO. New insights from small rhythmic circuits. Curr Opin Neurobiol 2022; 76:102610. [PMID: 35986971 DOI: 10.1016/j.conb.2022.102610] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/20/2022] [Accepted: 06/28/2022] [Indexed: 11/30/2022]
Abstract
Small rhythmic circuits, such as those found in invertebrates, have provided fundamental insights into how circuit dynamics depend on individual neuronal and synaptic properties. Degenerate circuits are those with different network parameters and similar behavior. New work on degenerate circuits and their modulation illustrates some of the rules that help maintain stable and robust circuit function despite environmental perturbations. Advances in neuropeptide isolation and identification provide enhanced understanding of the neuromodulation of circuits for behavior. The advent of molecular studies of mRNA expression provides new insight into animal-to-animal variability and the homeostatic regulation of excitability in neurons and networks.
Collapse
Affiliation(s)
- Eve Marder
- Volen Center and Biology Department, Brandeis University, Waltham, MA 02454, USA
| | - Sonal Kedia
- Volen Center and Biology Department, Brandeis University, Waltham, MA 02454, USA. https://twitter.com/Sonal_Kedia
| | - Ekaterina O Morozova
- Volen Center and Biology Department, Brandeis University, Waltham, MA 02454, USA.
| |
Collapse
|
6
|
Rue MC, Alonso LM, Marder E. Repeated applications of high potassium elicit long-term changes in a motor circuit from the crab, Cancer borealis. iScience 2022; 25:104919. [PMID: 36060056 PMCID: PMC9436765 DOI: 10.1016/j.isci.2022.104919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 07/12/2022] [Accepted: 08/08/2022] [Indexed: 12/04/2022] Open
Abstract
We examined the effects of altered extracellular potassium concentration on the output of the well-studied pyloric circuit in the crab, Cancer borealis. Pyloric neurons initially become quiescent, then recover spiking and bursting activity in high potassium saline (2.5x[K+]). These changes in circuit robustness are maintained after the perturbation is removed; pyloric neurons are more robust to subsequent potassium perturbations even after several hours of wash in control saline. Despite this long-term "memory" of the stimulus history, we found no differences in neuronal activity in control saline. The circuit's adaptation is erased by both low potassium saline (0.4x[K+]) and direct hyperpolarizing current. Initial sensitivity of PD neurons to high potassium saline also varies seasonally, indicating that changes in robustness may reflect natural changes in circuit states. Thus, perturbation, followed by recovery of normal activity, can hide cryptic changes in neuronal properties that are only revealed by subsequent challenges.
Collapse
Affiliation(s)
- Mara C.P. Rue
- Biology Department and Volen Center, Brandeis University, Waltham, MA 02454, USA
| | - Leandro M. Alonso
- Biology Department and Volen Center, Brandeis University, Waltham, MA 02454, USA
| | - Eve Marder
- Biology Department and Volen Center, Brandeis University, Waltham, MA 02454, USA,Corresponding author
| |
Collapse
|
7
|
Taylor JD, Chauhan AS, Taylor JT, Shilnikov AL, Nogaret A. Noise-activated barrier crossing in multiattractor dissipative neural networks. Phys Rev E 2022; 105:064203. [PMID: 35854623 DOI: 10.1103/physreve.105.064203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 05/17/2022] [Indexed: 06/15/2023]
Abstract
Noise-activated transitions between coexisting attractors are investigated in a chaotic spiking network. At low noise level, attractor hopping consists of discrete bifurcation events that conserve the memory of initial conditions. When the escape probability becomes comparable to the intrabasin hopping probability, the lifetime of attractors is given by a detailed balance where the less coherent attractors act as a sink for the more coherent ones. In this regime, the escape probability follows an activation law allowing us to assign pseudoactivation energies to limit cycle attractors. These pseudoenergies introduce a useful metric for evaluating the resilience of biological rhythms to perturbations.
Collapse
Affiliation(s)
- Joseph D Taylor
- Department of Physics, University of Bath, Bath BA2 7AY, United Kingdom
| | - Ashok S Chauhan
- Department of Physics, University of Bath, Bath BA2 7AY, United Kingdom
| | - John T Taylor
- Department of Electronics and Electrical Engineering, University of Bath, Bath BA2 7AY, United Kingdom
| | - Andrey L Shilnikov
- Neuroscience Institute, Georgia State University, Petit Science Center, 100 Piedmont Avenue Atlanta, Georgia 30303, USA
- Department of Mathematics and Statistics, Georgia State University, Petit Science Center, 100 Piedmont Avenue, Atlanta, Georgia 30303, USA
| | - Alain Nogaret
- Department of Physics, University of Bath, Bath BA2 7AY, United Kingdom
| |
Collapse
|
8
|
Approaches to Parameter Estimation from Model Neurons and Biological Neurons. ALGORITHMS 2022. [DOI: 10.3390/a15050168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Model optimization in neuroscience has focused on inferring intracellular parameters from time series observations of the membrane voltage and calcium concentrations. These parameters constitute the fingerprints of ion channel subtypes and may identify ion channel mutations from observed changes in electrical activity. A central question in neuroscience is whether computational methods may obtain ion channel parameters with sufficient consistency and accuracy to provide new information on the underlying biology. Finding single-valued solutions in particular, remains an outstanding theoretical challenge. This note reviews recent progress in the field. It first covers well-posed problems and describes the conditions that the model and data need to meet to warrant the recovery of all the original parameters—even in the presence of noise. The main challenge is model error, which reflects our lack of knowledge of exact equations. We report on strategies that have been partially successful at inferring the parameters of rodent and songbird neurons, when model error is sufficiently small for accurate predictions to be made irrespective of stimulation.
Collapse
|
9
|
Gorur-Shandilya S, Cronin EM, Schneider AC, Haddad SA, Rosenbaum P, Bucher D, Nadim F, Marder E. Mapping circuit dynamics during function and dysfunction. eLife 2022; 11:e76579. [PMID: 35302489 PMCID: PMC9000962 DOI: 10.7554/elife.76579] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 03/18/2022] [Indexed: 11/13/2022] Open
Abstract
Neural circuits can generate many spike patterns, but only some are functional. The study of how circuits generate and maintain functional dynamics is hindered by a poverty of description of circuit dynamics across functional and dysfunctional states. For example, although the regular oscillation of a central pattern generator is well characterized by its frequency and the phase relationships between its neurons, these metrics are ineffective descriptors of the irregular and aperiodic dynamics that circuits can generate under perturbation or in disease states. By recording the circuit dynamics of the well-studied pyloric circuit in Cancer borealis, we used statistical features of spike times from neurons in the circuit to visualize the spike patterns generated by this circuit under a variety of conditions. This approach captures both the variability of functional rhythms and the diversity of atypical dynamics in a single map. Clusters in the map identify qualitatively different spike patterns hinting at different dynamic states in the circuit. State probability and the statistics of the transitions between states varied with environmental perturbations, removal of descending neuromodulatory inputs, and the addition of exogenous neuromodulators. This analysis reveals strong mechanistically interpretable links between complex changes in the collective behavior of a neural circuit and specific experimental manipulations, and can constrain hypotheses of how circuits generate functional dynamics despite variability in circuit architecture and environmental perturbations.
Collapse
Affiliation(s)
| | - Elizabeth M Cronin
- Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers UniversityNewarkUnited States
| | - Anna C Schneider
- Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers UniversityNewarkUnited States
| | - Sara Ann Haddad
- Volen Center and Biology Department, Brandeis UniversityWalthamUnited States
| | - Philipp Rosenbaum
- Volen Center and Biology Department, Brandeis UniversityWalthamUnited States
| | - Dirk Bucher
- Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers UniversityNewarkUnited States
| | - Farzan Nadim
- Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers UniversityNewarkUnited States
| | - Eve Marder
- Volen Center and Biology Department, Brandeis UniversityWalthamUnited States
| |
Collapse
|
10
|
Marder E, Rue MCP. From the Neuroscience of Individual Variability to Climate Change. J Neurosci 2021; 41:10213-10221. [PMID: 34753741 PMCID: PMC8672684 DOI: 10.1523/jneurosci.1261-21.2021] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 10/28/2021] [Accepted: 11/01/2021] [Indexed: 11/21/2022] Open
Abstract
Years of basic neuroscience on the modulation of the small circuits found in the crustacean stomatogastric ganglion have led us to study the effects of temperature on the motor patterns produced by the stomatogastric ganglion. While the impetus for this work was the study of individual variability in the parameters determining intrinsic and synaptic conductances, we are confronting substantial fluctuations in the stability of the networks to extreme temperature; these may correlate with changes in ocean temperature. Interestingly, when studied under control conditions, these wild-caught animals appear to be unchanged, but it is only when challenged by extreme temperatures that we reveal the consequences of warming oceans.
Collapse
Affiliation(s)
- Eve Marder
- Volen Center and Biology Department, Brandeis University, Waltham, Massachusetts 02454
| | - Mara C P Rue
- Volen Center and Biology Department, Brandeis University, Waltham, Massachusetts 02454
| |
Collapse
|
11
|
Cook AP, Nusbaum MP. Feeding state-dependent modulation of feeding-related motor patterns. J Neurophysiol 2021; 126:1903-1924. [PMID: 34669505 PMCID: PMC8715047 DOI: 10.1152/jn.00387.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/12/2021] [Accepted: 10/13/2021] [Indexed: 11/22/2022] Open
Abstract
Studies elucidating modulation of microcircuit activity in isolated nervous systems have revealed numerous insights regarding neural circuit flexibility, but this approach limits the link between experimental results and behavioral context. To bridge this gap, we studied feeding behavior-linked modulation of microcircuit activity in the isolated stomatogastric nervous system (STNS) of male Cancer borealis crabs. Specifically, we removed hemolymph from a crab that was unfed for ≥24 h ("unfed" hemolymph) or fed 15 min to 2 h before hemolymph removal ("fed" hemolymph). After feeding, the first significant foregut emptying occurred >1 h later and complete emptying required ≥6 h. We applied the unfed or fed hemolymph to the stomatogastric ganglion (STG) in an isolated STNS preparation from a separate, unfed crab to determine its influence on the VCN (ventral cardiac neuron)-triggered gastric mill (chewing) and pyloric (filtering of chewed food) rhythms. Unfed hemolymph had little influence on these rhythms, but fed hemolymph from each examined time-point (15 min, 1 h, or 2 h after feeding) slowed one or both rhythms without weakening circuit neuron activity. There were also distinct parameter changes associated with each time-point. One change unique to the 1-h time-point (i.e., reduced activity of one circuit neuron during the transition from the gastric mill retraction to protraction phase) suggested that the fed hemolymph also enhanced the influence of a projection neuron that innervates the STG from a ganglion isolated from the applied hemolymph. Hemolymph thus provides a feeding state-dependent modulation of the two feeding-related motor patterns in the C. borealis STG.NEW & NOTEWORTHY Little is known about behavior-linked modulation of microcircuit activity. We show that the VCN-triggered gastric mill (chewing) and pyloric (food filtering) rhythms in the isolated crab Cancer borealis stomatogastric nervous system were changed by applying hemolymph from recently fed but not unfed crabs. This included some distinct parameter changes during each examined post-fed hemolymph time-point. These results suggest the presence of feeding-related changes in circulating hormones that regulate consummatory microcircuit activity.
Collapse
Affiliation(s)
- Aaron P Cook
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Michael P Nusbaum
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| |
Collapse
|
12
|
Powell DJ, Marder E, Nusbaum MP. Perturbation-specific responses by two neural circuits generating similar activity patterns. Curr Biol 2021; 31:4831-4838.e4. [PMID: 34506730 DOI: 10.1016/j.cub.2021.08.042] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/07/2021] [Accepted: 08/13/2021] [Indexed: 01/30/2023]
Abstract
A fundamental question in neuroscience is whether neuronal circuits with variable circuit parameters that produce similar outputs respond comparably to equivalent perturbations.1-4 Work on the pyloric rhythm of the crustacean stomatogastric ganglion (STG) showed that highly variable sets of intrinsic and synaptic conductances can generate similar circuit activity patterns.5-9 Importantly, in response to physiologically relevant perturbations, these disparate circuit solutions can respond robustly and reliably,10-12 but when exposed to extreme perturbations the underlying circuit parameter differences produce diverse patterns of disrupted activity.7,12,13 In this example, the pyloric circuit is unchanged; only the conductance values vary. In contrast, the gastric mill rhythm in the STG can be generated by distinct circuits when activated by different modulatory neurons and/or neuropeptides.14-21 Generally, these distinct circuits produce different gastric mill rhythms. However, the rhythms driven by stimulating modulatory commissural neuron 1 (MCN1) and bath-applying CabPK (Cancer borealis pyrokinin) peptide generate comparable output patterns, despite having distinct circuits that use separate cellular and synaptic mechanisms.22-25 Here, we use these two gastric mill circuits to determine whether such circuits respond comparably when challenged with persisting (hormonal: CCAP) or acute (sensory: GPR neuron) metabotropic influences. Surprisingly, the hormone-mediated action separates these two rhythms despite activating the same ionic current in the same circuit neuron during both rhythms, whereas the sensory neuron evokes comparable responses despite acting via different synapses during each rhythm. These results highlight the need for caution when inferring the circuit response to a perturbation when that circuit is not well defined physiologically.
Collapse
Affiliation(s)
- Daniel J Powell
- Volen Center for Complex Systems and Department of Biology, Brandeis University, 415 South Street, Waltham, MA 02454, USA
| | - Eve Marder
- Volen Center for Complex Systems and Department of Biology, Brandeis University, 415 South Street, Waltham, MA 02454, USA
| | - Michael P Nusbaum
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, 211 CRB, 415 Curie Boulevard, Philadelphia, PA 19104, USA.
| |
Collapse
|
13
|
Kelley C, Dura-Bernal S, Neymotin SA, Antic SD, Carnevale NT, Migliore M, Lytton WW. Effects of Ih and TASK-like shunting current on dendritic impedance in layer 5 pyramidal-tract neurons. J Neurophysiol 2021; 125:1501-1516. [PMID: 33689489 PMCID: PMC8282219 DOI: 10.1152/jn.00015.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 03/02/2021] [Accepted: 03/02/2021] [Indexed: 02/07/2023] Open
Abstract
Pyramidal neurons in neocortex have complex input-output relationships that depend on their morphologies, ion channel distributions, and the nature of their inputs, but which cannot be replicated by simple integrate-and-fire models. The impedance properties of their dendritic arbors, such as resonance and phase shift, shape neuronal responses to synaptic inputs and provide intraneuronal functional maps reflecting their intrinsic dynamics and excitability. Experimental studies of dendritic impedance have shown that neocortical pyramidal tract neurons exhibit distance-dependent changes in resonance and impedance phase with respect to the soma. We, therefore, investigated how well several biophysically detailed multicompartment models of neocortical layer 5 pyramidal tract neurons reproduce the location-dependent impedance profiles observed experimentally. Each model tested here exhibited location-dependent impedance profiles, but most captured either the observed impedance amplitude or phase, not both. The only model that captured features from both incorporates hyperpolarization-activated cyclic nucleotide-gated (HCN) channels and a shunting current, such as that produced by Twik-related acid-sensitive K+ (TASK) channels. TASK-like channel density in this model was proportional to local HCN channel density. We found that although this shunting current alone is insufficient to produce resonance or realistic phase response, it modulates all features of dendritic impedance, including resonance frequencies, resonance strength, synchronous frequencies, and total inductive phase. We also explored how the interaction of HCN channel current (Ih) and a TASK-like shunting current shape synaptic potentials and produce degeneracy in dendritic impedance profiles, wherein different combinations of Ih and shunting current can produce the same impedance profile.NEW & NOTEWORTHY We simulated chirp current stimulation in the apical dendrites of 5 biophysically detailed multicompartment models of neocortical pyramidal tract neurons and found that a combination of HCN channels and TASK-like channels produced the best fit to experimental measurements of dendritic impedance. We then explored how HCN and TASK-like channels can shape the dendritic impedance as well as the voltage response to synaptic currents.
Collapse
Affiliation(s)
- Craig Kelley
- Program in Biomedical Engineering, SUNY Downstate Health Sciences University and NYU Tandon School of Engineering, Brooklyn, New York
| | - Salvador Dura-Bernal
- Department of Physiology and Pharmacology, SUNY Downstate Health Sciences University, Brooklyn, New York
- Center for Biomedical Imaging and Neuromodulation, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, New York
| | - Samuel A Neymotin
- Center for Biomedical Imaging and Neuromodulation, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, New York
- Department of Psychiatry, NYU Grossman School of Medicine, New York City, New York
| | - Srdjan D Antic
- Neuroscience Department, Institute of Systems Genomics, University of Connecticut Health, Farmington, Connecticut
| | | | - Michele Migliore
- Institute of Biophysics, National Research Council, Palermo, Italy
| | - William W Lytton
- Program in Biomedical Engineering, SUNY Downstate Health Sciences University and NYU Tandon School of Engineering, Brooklyn, New York
- Department of Physiology and Pharmacology, SUNY Downstate Health Sciences University, Brooklyn, New York
- Department of Neurology, SUNY Downstate Health Sciences University, Brooklyn, New York
- Department of Neurology, Kings County Hospital Center, Brooklyn, New York
- The Robert F. Furchgott Center for Neural and Behavioral Science, Brooklyn, New York
| |
Collapse
|
14
|
Goaillard JM, Marder E. Ion Channel Degeneracy, Variability, and Covariation in Neuron and Circuit Resilience. Annu Rev Neurosci 2021; 44:335-357. [PMID: 33770451 DOI: 10.1146/annurev-neuro-092920-121538] [Citation(s) in RCA: 76] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The large number of ion channels found in all nervous systems poses fundamental questions concerning how the characteristic intrinsic properties of single neurons are determined by the specific subsets of channels they express. All neurons display many different ion channels with overlapping voltage- and time-dependent properties. We speculate that these overlapping properties promote resilience in neuronal function. Individual neurons of the same cell type show variability in ion channel conductance densities even though they can generate reliable and similar behavior. This complicates a simple assignment of function to any conductance and is associated with variable responses of neurons of the same cell type to perturbations, deletions, and pharmacological manipulation. Ion channel genes often show strong positively correlated expression, which may result from the molecular and developmental rules that determine which ion channels are expressed in a given cell type.
Collapse
Affiliation(s)
| | - Eve Marder
- Volen Center and Department of Biology, Brandeis University, Waltham, Massachusetts 02454, USA;
| |
Collapse
|
15
|
Ratliff J, Franci A, Marder E, O'Leary T. Neuronal oscillator robustness to multiple global perturbations. Biophys J 2021; 120:1454-1468. [PMID: 33610580 PMCID: PMC8105708 DOI: 10.1016/j.bpj.2021.01.038] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 12/07/2020] [Accepted: 01/07/2021] [Indexed: 11/29/2022] Open
Abstract
Neuronal activity depends on ion channels and biophysical processes that are strongly and differentially sensitive to physical variables such as temperature and pH. Nonetheless, neuronal oscillators can be surprisingly resilient to perturbations in these variables. We study a three-neuron pacemaker ensemble that drives the pyloric rhythm of the crab, Cancer borealis. These crabs routinely experience a number of global perturbations, including changes in temperature and pH. Although pyloric oscillations are robust to such changes, for sufficiently large deviations the rhythm reversibly breaks down. As temperature increases beyond a tipping point, oscillators transition to silence. Acidic pH deviations also show tipping points, with a reliable transition first to tonic spiking, then to silence. Surprisingly, robustness to perturbations in pH only moderately affects temperature robustness. Consistent with high animal-to-animal variability in biophysical circuit parameters, tipping points in temperature and pH vary across animals. However, the ordering and discrete classes of transitions at critical points are conserved. This implies that qualitative oscillator dynamics are preserved across animals despite high quantitative parameter variability. A universal model of bursting dynamics predicts the existence of these transition types and the order in which they occur.
Collapse
Affiliation(s)
- Jacob Ratliff
- Dominick P Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York
| | - Alessio Franci
- Department of Mathematics, National Autonomous University of Mexico, Mexico City, Mexico
| | - Eve Marder
- Biology Department, Volen Center, Brandeis University, Waltham, Massachusetts.
| | - Timothy O'Leary
- Department of Engineering, University of Cambridge, Cambridge, United Kingdom.
| |
Collapse
|
16
|
Powell D, Haddad SA, Gorur-Shandilya S, Marder E. Coupling between fast and slow oscillator circuits in Cancer borealis is temperature-compensated. eLife 2021; 10:60454. [PMID: 33538245 PMCID: PMC7889077 DOI: 10.7554/elife.60454] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 02/01/2021] [Indexed: 12/21/2022] Open
Abstract
Coupled oscillatory circuits are ubiquitous in nervous systems. Given that most biological processes are temperature-sensitive, it is remarkable that the neuronal circuits of poikilothermic animals can maintain coupling across a wide range of temperatures. Within the stomatogastric ganglion (STG) of the crab, Cancer borealis, the fast pyloric rhythm (~1 Hz) and the slow gastric mill rhythm (~0.1 Hz) are precisely coordinated at ~11°C such that there is an integer number of pyloric cycles per gastric mill cycle (integer coupling). Upon increasing temperature from 7°C to 23°C, both oscillators showed similar temperature-dependent increases in cycle frequency, and integer coupling between the circuits was conserved. Thus, although both rhythms show temperature-dependent changes in rhythm frequency, the processes that couple these circuits maintain their coordination over a wide range of temperatures. Such robustness to temperature changes could be part of a toolbox of processes that enables neural circuits to maintain function despite global perturbations.
Collapse
Affiliation(s)
- Daniel Powell
- Biology Department and Volen Center, Brandeis University, Waltham, United States
| | - Sara A Haddad
- Biology Department and Volen Center, Brandeis University, Waltham, United States
| | | | - Eve Marder
- Biology Department and Volen Center, Brandeis University, Waltham, United States
| |
Collapse
|
17
|
Stein W, Harzsch S. The Neurobiology of Ocean Change - insights from decapod crustaceans. ZOOLOGY 2021; 144:125887. [PMID: 33445148 DOI: 10.1016/j.zool.2020.125887] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 12/01/2020] [Accepted: 12/02/2020] [Indexed: 12/27/2022]
Abstract
The unprecedented rate of carbon dioxide accumulation in the atmosphere has led to increased warming, acidification and oxygen depletion in the world's oceans, with projected impacts also on ocean salinity. In this perspective article, we highlight potential impacts of these factors on neuronal responses in decapod crustaceans. Decapod crustaceans comprise more than 8,800 marine species which have colonized a wide range of habitats that are particularly affected by global ocean change, including estuarine, intertidal, and coastal areas. Many decapod species have large economic value and high ecological importance because of their global invasive potential and impact on local ecosystems. Global warming has already led to considerable changes in decapod species' behavior and habitat range. Relatively little is known about how the decapod nervous system, which is the ultimate driver of all behaviors, copes with environmental stressors. We use select examples to summarize current findings and evaluate the impact of current and expected environmental changes. While data indicate a surprising robustness against stressors like temperature and pH, we find that only a handful of species have been studied and long-term effects on neuronal activity remain mostly unknown. A further conclusion is that the combined effects of multiple stressors are understudied. We call for greater research efforts towards long-term effects on neuronal physiology and expansion of cross-species comparisons to address these issues.
Collapse
Affiliation(s)
- Wolfgang Stein
- Illinois State University, School of Biological Sciences, Normal, IL 61790, USA.
| | - Steffen Harzsch
- University of Greifswald, Zoological Institute and Museum, Department of Cytology and Evolutionary Biology, D-17498 Greifswald, Germany.
| |
Collapse
|
18
|
Activity-dependent compensation of cell size is vulnerable to targeted deletion of ion channels. Sci Rep 2020; 10:15989. [PMID: 32994529 PMCID: PMC7524806 DOI: 10.1038/s41598-020-72977-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 08/25/2020] [Indexed: 01/13/2023] Open
Abstract
In many species, excitable cells preserve their physiological properties despite significant variation in physical size across time and in a population. For example, neurons in crustacean central pattern generators generate similar firing patterns despite several-fold increases in size between juveniles and adults. This presents a biophysical problem because the electrical properties of cells are highly sensitive to membrane area and channel density. It is not known whether specific mechanisms exist to sense membrane area and adjust channel expression to keep a consistent channel density, or whether regulation mechanisms that sense activity alone are capable of compensating cell size. We show that destabilising effects of growth can be specifically compensated by feedback mechanism that senses average calcium influx and jointly regulate multiple conductances. However, we further show that this class of growth-compensating regulation schemes is necessarily sensitive to perturbations that alter the expression of subsets of ion channel types. Targeted perturbations of specific ion channels can trigger a pathological response of the regulation mechanism and a failure of homeostasis. Our findings suggest that physiological regulation mechanisms that confer robustness to growth may be specifically vulnerable to deletions or mutations that affect subsets of ion channels.
Collapse
|
19
|
Estimation of neuron parameters from imperfect observations. PLoS Comput Biol 2020; 16:e1008053. [PMID: 32673311 PMCID: PMC7386621 DOI: 10.1371/journal.pcbi.1008053] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 07/28/2020] [Accepted: 06/15/2020] [Indexed: 12/21/2022] Open
Abstract
The estimation of parameters controlling the electrical properties of biological neurons is essential to determine their complement of ion channels and to understand the function of biological circuits. By synchronizing conductance models to time series observations of the membrane voltage, one may construct models capable of predicting neuronal dynamics. However, identifying the actual set of parameters of biological ion channels remains a formidable theoretical challenge. Here, we present a regularization method that improves convergence towards this optimal solution when data are noisy and the model is unknown. Our method relies on the existence of an offset in parameter space arising from the interplay between model nonlinearity and experimental error. By tuning this offset, we induce saddle-node bifurcations from sub-optimal to optimal solutions. This regularization method increases the probability of finding the optimal set of parameters from 67% to 94.3%. We also reduce parameter correlations by implementing adaptive sampling and stimulation protocols compatible with parameter identifiability requirements. Our results show that the optimal model parameters may be inferred from imperfect observations provided the conditions of observability and identifiability are fulfilled.
Collapse
|
20
|
Alonso LM, Marder E. Temperature compensation in a small rhythmic circuit. eLife 2020; 9:e55470. [PMID: 32484437 PMCID: PMC7332291 DOI: 10.7554/elife.55470] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 05/31/2020] [Indexed: 12/28/2022] Open
Abstract
Temperature affects the conductances and kinetics of the ionic channels that underlie neuronal activity. Each membrane conductance has a different characteristic temperature sensitivity, which raises the question of how neurons and neuronal circuits can operate robustly over wide temperature ranges. To address this, we employed computational models of the pyloric network of crabs and lobsters. We produced multiple different models that exhibit a triphasic pyloric rhythm over a range of temperatures and explored the dynamics of their currents and how they change with temperature. Temperature can produce smooth changes in the relative contributions of the currents to neural activity so that neurons and networks undergo graceful transitions in the mechanisms that give rise to their activity patterns. Moreover, responses of the models to deletions of a current can be different at high and low temperatures, indicating that even a well-defined genetic or pharmacological manipulation may produce qualitatively distinct effects depending on the temperature.
Collapse
Affiliation(s)
- Leandro M Alonso
- Volen Center and Biology Department, Brandeis UniversityWalthamUnited States
| | - Eve Marder
- Volen Center and Biology Department, Brandeis UniversityWalthamUnited States
| |
Collapse
|
21
|
He LS, Rue MCP, Morozova EO, Powell DJ, James EJ, Kar M, Marder E. Rapid adaptation to elevated extracellular potassium in the pyloric circuit of the crab, Cancer borealis. J Neurophysiol 2020; 123:2075-2089. [PMID: 32319837 DOI: 10.1152/jn.00135.2020] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Elevated potassium concentration ([K+]) is often used to alter excitability in neurons and networks by shifting the potassium equilibrium potential (EK) and, consequently, the resting membrane potential. We studied the effects of increased extracellular [K+] on the well-described pyloric circuit of the crab Cancer borealis. A 2.5-fold increase in extracellular [K+] (2.5×[K+]) depolarized pyloric dilator (PD) neurons and resulted in short-term loss of their normal bursting activity. This period of silence was followed within 5-10 min by the recovery of spiking and/or bursting activity during continued superfusion of 2.5×[K+] saline. In contrast, when PD neurons were pharmacologically isolated from pyloric presynaptic inputs, they exhibited no transient loss of spiking activity in 2.5×[K+], suggesting the presence of an acute inhibitory effect mediated by circuit interactions. Action potential threshold in PD neurons hyperpolarized during an hour-long exposure to 2.5×[K+] concurrent with the recovery of spiking and/or bursting activity. Thus the initial loss of activity appears to be mediated by synaptic interactions within the network, but the secondary adaptation depends on changes in the intrinsic excitability of the pacemaker neurons. The complex sequence of events in the responses of pyloric neurons to elevated [K+] demonstrates that electrophysiological recordings are necessary to determine both the transient and longer term effects of even modest alterations of K+ concentrations on neuronal activity.NEW & NOTEWORTHY Solutions with elevated extracellular potassium are commonly used as a depolarizing stimulus. We studied the effects of high potassium concentration ([K+]) on the pyloric circuit of the crab stomatogastric ganglion. A 2.5-fold increase in extracellular [K+] caused a transient loss of activity that was not due to depolarization block, followed by a rapid increase in excitability and recovery of spiking within minutes. This suggests that changing extracellular potassium can have complex and nonstationary effects on neuronal circuits.
Collapse
Affiliation(s)
- Lily S He
- Biology Department and Volen Center, Brandeis University, Waltham, Massachusetts
| | - Mara C P Rue
- Biology Department and Volen Center, Brandeis University, Waltham, Massachusetts
| | - Ekaterina O Morozova
- Biology Department and Volen Center, Brandeis University, Waltham, Massachusetts
| | - Daniel J Powell
- Biology Department and Volen Center, Brandeis University, Waltham, Massachusetts
| | - Eric J James
- Biology Department, Adelphi University, Garden City, New York
| | - Manaswini Kar
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Eve Marder
- Biology Department and Volen Center, Brandeis University, Waltham, Massachusetts
| |
Collapse
|
22
|
Santin JM. Motor inactivity in hibernating frogs: Linking plasticity that stabilizes neuronal function to behavior in the natural environment. Dev Neurobiol 2019; 79:880-891. [DOI: 10.1002/dneu.22721] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 09/07/2019] [Accepted: 09/30/2019] [Indexed: 12/12/2022]
Affiliation(s)
- Joseph M. Santin
- Department of BiologyUniversity of North Carolina at Greensboro Greensboro North Carolina
| |
Collapse
|
23
|
Martinez D, Santin JM, Schulz D, Nadim F. The differential contribution of pacemaker neurons to synaptic transmission in the pyloric network of the Jonah crab, Cancer borealis. J Neurophysiol 2019; 122:1623-1633. [PMID: 31411938 DOI: 10.1152/jn.00038.2019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Many neurons receive synchronous input from heterogeneous presynaptic neurons with distinct properties. An instructive example is the crustacean stomatogastric pyloric circuit pacemaker group, consisting of the anterior burster (AB) and pyloric dilator (PD) neurons, which are active synchronously and exert a combined synaptic action on most pyloric follower neurons. Previous studies in lobster have indicated that AB is glutamatergic, whereas PD is cholinergic. However, although the stomatogastric system of the crab Cancer borealis has become a preferred system for exploration of cellular and synaptic basis of circuit dynamics, the pacemaker synaptic output has not been carefully analyzed in this species. We examined the synaptic properties of these neurons using a combination of single-cell mRNA analysis, electrophysiology, and pharmacology. The crab PD neuron expresses high levels of choline acetyltransferase and the vesicular acetylcholine transporter mRNAs, hallmarks of cholinergic neurons. In contrast, the AB neuron expresses neither cholinergic marker but expresses high levels of vesicular glutamate transporter mRNA, consistent with a glutamatergic phenotype. Notably, in the combined synapses to follower neurons, 70-75% of the total current was blocked by putative glutamatergic blockers, but short-term synaptic plasticity remained unchanged, and although the total pacemaker current in two follower neuron types was different, this difference did not contribute to the phasing of the follower neurons. These findings provide a guide for similar explorations of heterogeneous synaptic connections in other systems and a baseline in this system for the exploration of the differential influence of neuromodulators.NEW & NOTEWORTHY The pacemaker-driven pyloric circuit of the Jonah crab stomatogastric nervous system is a well-studied model system for exploring circuit dynamics and neuromodulation, yet the understanding of the synaptic properties of the two pacemaker neuron types is based on older analyses in other species. We use single-cell PCR and electrophysiology to explore the neurotransmitters used by the pacemaker neurons and their distinct contribution to the combined synaptic potentials.
Collapse
Affiliation(s)
- Diana Martinez
- Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers University, Newark, New Jersey
| | - Joseph M Santin
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, Missouri
| | - David Schulz
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, Missouri
| | - Farzan Nadim
- Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers University, Newark, New Jersey
| |
Collapse
|
24
|
Kushinsky D, Morozova EO, Marder E. In vivo effects of temperature on the heart and pyloric rhythms in the crab Cancer borealis. J Exp Biol 2019; 222:jeb199190. [PMID: 30630966 PMCID: PMC6432657 DOI: 10.1242/jeb.199190] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Accepted: 01/04/2019] [Indexed: 12/26/2022]
Abstract
The heart and pyloric rhythms of crustaceans have been studied separately and extensively over many years. Local and hormonal neuromodulation and sensory inputs into these central pattern generator circuits play a significant role in an animal's response to perturbations, but are usually lost or removed during in vitro studies. To examine simultaneously the in vivo motor output of the crustacean heart and pyloric rhythms, we used photoplethysmography. In the population measured (n=49), the heart rhythm frequency ranged from 0.3 to 2.3 Hz. The pyloric rhythm varied from 0.2 to 1.6 Hz. We observed a weak correlation between the frequencies of the heart and pyloric rhythms. During multiple hour-long recordings, many animals held at a controlled temperature showed strong inhibitory bouts in which the heart decreased in frequency or become quiescent and the pyloric rhythm decreased in frequency. We measured the simultaneous responses of the rhythms to temperature ramps by heating or cooling the saline bath while recording both the heart and pyloric muscle movements. Q10, critical temperature (temperature at which muscle function is compromised) and changes in frequency were calculated for each of the rhythms tested. The heart rhythm was more robust to high temperature than the pyloric rhythm.
Collapse
Affiliation(s)
- Dahlia Kushinsky
- Biology Department and Volen Center, Brandeis University, Waltham, MA 02454, USA
| | - Ekaterina O Morozova
- Biology Department and Volen Center, Brandeis University, Waltham, MA 02454, USA
| | - Eve Marder
- Biology Department and Volen Center, Brandeis University, Waltham, MA 02454, USA
| |
Collapse
|